VXLAN is a technology used to encapsulate a Layer 2 packet using a Layer 3 protocol. A principle of the VXLAN is as follows. A packet sent by a virtual machine is encapsulated into a User Datagram Protocol (UDP) packet, the UDP packet is encapsulated using an Internet Protocol (IP) address or a media access control (MAC) address of a physical network as an outer header, the encapsulated UDP packet is transmitted over the Internet, the encapsulated UDP packet is decapsulated by a destination node, and the decapsulated packet is sent to a target virtual machine.
FIG. 1 is a schematic structural diagram of VXLAN networking. As shown in FIG. 1, a VXLAN may be divided into three layers, an access layer, a convergence layer, and a core layer. An access node 4 at the access layer is a user-side access device directly connected to a virtual machine server 5, and the virtual machine server 5 accesses the VXLAN network using the access node 4. A convergence node 3 at the convergence layer is an intermediate node in a VXLAN link and used to forward data. A core node 2 at the core layer is connected to a wide area network (WAN) 6 using another node 1. A controller 7 is connected to each device in the VXLAN, and the controller 7 may deliver data to the device, and may query data information from the device in order to control the entire network. The core node 2 at the core layer is connected to all convergence nodes 3. The convergence node 3 is connected to all local access nodes 4. A dynamic routing protocol is configured between the core node 2 and the convergence node 3 and between the convergence node 3 and the access node 4. Data communication is performed between nodes using multiple equivalent paths. For ease of management, a concept of a VXLAN tunnel endpoint (VTEP) is introduced in the VXLAN standard. The VTEP is used to encapsulate and decapsulate a VXLAN packet. Both the access node 4 and the convergence node 3 in the VXLAN may be used as VTEPs. There may be multiple equivalent paths between every two VTEPs.
However, there are many VTEPs in the VXLAN, and there are multiple equivalent paths between the VTEPs. As a result, when a path between the VTEPs fails, the faulty path cannot be determined in a timely manner.